Carbapenem antibiotics represented by thienamycin have attracted attention as medicines because of their broad antimicrobial spectra.
Various processes for preparing carbapenem antibiotics have been reported, e.g., in Kametani, et al., Heterocycles, Vol. 17, pp. 463-506 (1982) and Shibuya, et al., Yuki Gosei Kagaku, Vol. 41, p. 62 (1983). Among the known processes, a process using(1'R,3R,4R)-4-acetoxy-3-(1'-hydroxyethyl)-azetidin-2-one or a derivative thereof represented by formula (IV): ##STR6## wherein R.sup.1 is as defined above, as an intermediate is particularly advantageous in that the compound of formula (IV) is reactive with various nucleophilic agents.
The intermediate compound of formula (IV) can be synthesized by, for example, the process disclosed in JP-A-2-134349 (corresponding to U.S. Pat. No. 4,981,992 and European Patent 369,691A) (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), which comprises acetoxylation of a (1'R,3S)-3-(1'-hydroxyethyl)azetidin-2-one derivative (I-B) as illustrated in the following reaction scheme. ##STR7## wherein R.sup.1, represents a hydroxyl-protective group.
Known techniques for lactamization of a .beta.-amino acid to obtain an azetidin-2-one skeleton as in Step (d) in the above reaction scheme include (1) utilization of Grignard reaction (see Robert W. Holley, et al., J. Am. Chem. Soc., Vol. 71, pp. 2124-2129 (1949), Scott Searrles, et al., Chemistry and Industry, p. 2097 (1964), and Leonhard Birkofer, et al., Ann. Chem., pp. 2195-2200 (1975)), (2) treatment with thionyl chloride-tertiary amine (see F. F. Blicks, et al., J. Org. Chem., Vol. 23, pp. 1102-1107 (1958)), (3) treatment with N,N'-dicyclohexylcarbodiimide (see D. G. Melillo, et al., Tetrahedron Lett., Vol. 21, pp. 2783-2786 (1980)), (4) use of a two liquid-liquid phase transfer system in which methylene chloride/H.sub.2 O: tetrabutylammonium hydrogensulfate is used as a phase transfer agent, and methanesulfonyl chloride and potassium hydrogen-carbonate are used as a cyclizing agent (see Yutaka Watanabe, et al., Chemistry Letters, pp. 443-444 (1981)), (5) treatment with 2-chloro-1-methylpyridium iodide (see Huamin Huang, et al., Chemistry Letters, pp. 1465-1466 (1984)), (6) treatment with bis-(5'-nitro-2'-pyridyl)-2,2,2-trichloroethylphosphinic acid (see Sunggak Kim, et al., Tetrahedron Lett., Vol. 28, pp. 2735-2736 (1987)), (7) treatment with diphenylphosphinic acid chloride (see Sunggak Kim, et al., J. Chem. Soc., Chem. Commun., pp. 1242-1243 (1988)), (8) treatment with a heterocyclic disulfide (e.g., 2,2'-dipyridyl disulfide, 2,2'-dibenzothiazolyl disulfide, and 2,2'-dibenzimidazolyl disulfide) and triphenylphosphine in the presence of an alkylnitrile [see JP-A-57-77670 (corresponding to European Patent 51,234B)], and (9) treatment with methanesulfonyl chloride and sodium hydrogencarbonate [see JP-A-2-17175 (corresponding to European Patent 343,716A)].
According to these processes, the yield of the lactam often depends on the structure of the reactant, .beta.-amino acid. Process (8) mentioned above is adopted in the conventional techniques for cyclizing(2S,3R)-2-aminomethyl-3-hydroxybutyric acid or a derivative thereof to obtain the corresponding lactam disclosed in David A. Evans, et al., Tetrahedron Lett., Vol. 27, No. 41, pp. 4961-4964 (1986), JP-A-63-297360 (corresponding to U.S. Pat. No. 4,927,507 and European Patent 290,385A), and JP-A-2-134349. More specifically, the reactant is treated with 2,2'-dipyridyl disulfide. However, 2,2'-dipyridyl disulfide is not only very expensive but unable to be recovered after the reaction. Hence, it has been demanded to develop a process for lactamization in good yield at low cost.
On the other hand, a sulfenamide represented by formula (III): ##STR8## wherein R.sup.2 represents ##STR9## and R.sup.3 and R.sup.4 each represent a hydrogen atom or a cyclic or acyclic hydrocarbon group, provided that they do not simultaneously represent a hydrogen atom, or R.sup.3 and R.sup.4 are taken together with the adjacent nitrogen atom to form a heterocyclic group, which is used as a reagent for lactamization in the present invention, is known to react with a thiazolinoazetidinone derivative in a water-containing organic solvent in the presence of an acid to open the thiazolyl ring thereof to obtain an intermediate for synthesizing cephalosporin type antibiotics as disclosed, e.g., in JP-A-59-44356 (corresponding to U.S. Pat. No. 4,622,178 and European Patent 117,875B). However, there is no case reported in which such a sulfenamide is used in synthesis of lactams.